Conventionally, a sliding member such as a cylinder block and a piston which is used in a lubricant oil needs to reduce a mechanical loss, in order to lower energy consumption and the like. For this reason, it is investigated to decrease the friction of the above described sliding member.
For instance, a carbon-coated sliding member is known which has a carbon coating film such as a diamond-like carbon coating film (hereinafter occasionally abbreviated as DLC coating film) provided on the surface of the above described sliding member (for instance, see Patent Literatures 1 and 2), in order to decrease the friction of the sliding member.
The above described carbon-coated sliding member can be produced, for instance, by a plasma CVD device. The above described plasma CVD device supplies a source gas to the inside of a workpiece such as an electroconductive sliding member, of which the inside is kept at a predetermined degree of vacuum, and simultaneously applies a negative bias voltage to the workpiece which is set as a cathode. As a result of the above operation, a potential difference occurs between an anode provided in the above described plasma CVD device, and the workpiece which is set as the above described cathode, and an electric discharge occurs. The above described electric discharge enables a plasma of the above described source gas to be generated in the inside of the above described workpiece.
Here, a hydrocarbon gas such as acetylene is used as the above described source gas, and thereby a plasma mainly of carbon can be generated in the inside of the above described workpiece. As a result, the above described plasma of carbon enables carbon and the like to be deposited on an inner surface of the above described workpiece, and enables a carbon coating film, for instance, such as the above described DLC coating film, to be formed thereon (for instance, see Patent Literature 3).